25. A researcher wishes to see if there is a difference in the fuel economy for city driving for three different types of automobiles: compact cars, sedans, and luxury cars. He randomly samples...

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Extracted text: 25. A researcher wishes to see if there is a difference in the fuel economy for city driving for three different types of automobiles: compact cars, sedans, and luxury cars. He randomly samples automobiles from each class and records the mileage (in miles per gallon - mpg). At a = 0.05 is there evidence to suggest there is some difference in the mean fuel economy of the vehicle types? Use the Excel output shown below to answer each question. One factor ANOVA Mean n Std. Dev 4.57 Compact 37.3 (a) State the null and alternative hypothe- 35.4 6.11 Sedan 26.0 2.65 Luxury ses. 3 33.7 12 6.53 Total (b) Indentify the test statistic. ANOVA table Source F p-value df MS 4.83 (c) Identify the p-value. Treatment 242.72 2 121.358 .0375 Error Total 225.95 468.67 9 25.106 11 (d) Draw a conclusion about H, and make a statement about the claim. Post hoc analysis p-values for pairwise t-tests Luxury 26.0 (e) What conclusions can we draw from the post hoc analysis? Sedan Compact 35.4 37.3 26.0 Luxury Sedan .0302 .0165 35.4 Compact 37.3 5954